Reef block



FIG. 1 is a first perspective view of a reef block;

FIG. 2 is a second perspective view thereof;

FIG. 3 is a top view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a first side view thereof;

FIG. 6 is a second side view thereof;

FIG. 7 is a front view thereof; and,

FIG. 8 is a back view thereof.

The broken lines in FIGS. 1 to 3 and 5 to 8 illustrate portions of thereef block that form no part of the claimed design.

CLAIM The ornamental design for a reef block, as shown and described.